Devices for medical use, or medical devices, include swallowable medical devices (particularly, capsule medical devices) that are swallowed by a subject to enter the subject's body, where they can traverse a passage in the body cavity to capture images of a target site inside the passage in the body cavity. The capsule medical devices described above have a configuration in which an image-acquisition device that can be used for the above medical treatment, for example, a charge-coupled device (CCD), which can acquire images, is provided for performing image acquisition at the target site inside the passage in the body cavity.
However, the above-described capsule medical device has to be guided through the passage in the body cavity in order to reach a target site. To guide the capsule medical device, it is necessary to detect its position in the passage in the body cavity.
Therefore, some techniques have been proposed for detecting the position of, for example, a capsule medical device guided to a site where its position cannot be visually checked (such as a body cavity). (For example, see Patent Document 1.)
Patent Document 1:
PCT International Publication No. WO 2004/014225 Pamphlet